Treating and Controlling Pond Algae

Pond algae is a completely normal part of a pond, particularly one that is new and still finding its balance. However, if you’re finding your pond has an excessive amount of algae growing, you might like to change some of your methods or incorporate a few treatments to manage it.

In this blog, we take a look at how you can treat and control algae in your pond.

Types of algae

When it comes to algae, not all types look and act the same. Familiarise yourself with the differences between common varieties and you’ll better know how to deal with them. The two types we are covering below are suspended algae and string algae.

Suspended algae

Sometimes also called floating algae, this type of algae can turn water green and cloudy. Suspended algae can produce at a rapid rate, which can turn a pond murky and green if left untreated. Another point with suspended algae is that it has small cells, which means filtration media often can’t pick it up.

What causes suspended algae?

A suspended algae bloom is often caused by an imbalance in the pond. It can happen when the pond catches too much sunlight or there are excess nutrients due to a lack of quality pond filtration, overfeeding of fish, stormwater runoff, or other reasons. You may notice a proliferation of floating algae in the spring, when the sun begins to heat the pond again, but fish and plants are still a little inactive from the winter cool.

Prevention and solutions

If caused by the changing temperatures, suspended algae may simply clear up on its own once the temperatures get warmer and beneficial bacteria begins to colonise the biological filter and aquatic plants begin to consume more nutrients. If the algae doesn’t clear up on its own, it may be time to change up a few things about your pond.

For one, your pond might be receiving a little too much direct sunlight. This can cause single-celled algae to proliferate. To mitigate this, provide more shade to your pond’s surface. Providing more shade can include adding in surface plants such as water lilies. You might also like to incorporate other pond plants that compete with the algae for nutrients.

Sometimes having too many fish in a pond can also cause a proliferation of suspended algae due to the excess waste production. Before adding fish to a pond, you should check to make sure you’re not putting in more than the feature can handle. Overfeeding a normal number of fish can also cause excess amounts of floating algae to form due to the remaining excess nutrients left in the water.

Treatment for suspended algae

If you’re looking to actively treat an outbreak of suspended algae in your pond, there are products available. At Aquascape Australia we stock Clear for Ponds, a concentrated formula designed to clear cloudy or discoloured water. This product contains a blend of clarifiers designed to clear suspended debris and reduce debris that attaches to rocks and gravel as well as a powerful phosphate binder that locks up excess nutrients. Clear for Ponds is safe for plants, pets, fish, and wildlife. Another product used to control suspended algae is a UV Clarifier that can be found in the UltraKlean Pressure Filters, these filters are used in conjunction with a dirty water pump such as the AquaForce to either spot treat the pond or continually use as filtration for the pond.

String algae

This type of algae can often be found attached to plant and rocks. It is a form of filamentous algae, with strings that clump together.

What causes string algae

String algae proliferation is also caused by an imbalance in the pond – typically excess sunlight or nutrients. This type of algae is tough, and the spores can reproduce easily within a pond.

Prevention and solutions

Similarly to suspended algae prevention, overgrowth of string algae can be mitigated by removing excess nutrients in a pond. This means ensuring you do not put too many fish into your pond, and making sure you don’t overfeed the fish. If there is excess fish food left over, be sure to scoop it out, rather than leaving it to sit in the water feature.

Provide enough shade to your pond. Ideally, two-thirds of your water surface should be shaded. To do this, incorporate surface plants or other margin plants around the feature. Bring in plants that will consume excess nutrients, that will compete with the algae.

You can also physically remove string algae from your pond using a pond skimmer or other implement. If doing so, make sure you are gentle and efficient, as the spores from the algae can separate and be released into the pond during the process.

Treatment for string algae

Excessive string algae blooms can also be treated with SAB Steam & Pond Cleaner (coming soon) which contains a combination of concentrated beneficial bacteria and enzymes that help to provide clean, clear, and healthy water conditions in ponds and waterfalls. The powerful combination of strong, natural cleaners helps to break down organic debris and maintain a biological balance in your feature while the phosphate binder prevents water quality issues. This allows you to spend more time enjoying your water feature and less time maintaining it. SAB Stream & Pond Cleaner will also help to reduce ammonia and nitrite. Treatments are easily measured with one scoop, making applications accurate and simple. Aquascape SAB Stream & Pond Cleaner is safe for fish, plants, pets, and wildlife.

Clear for Ponds is another simple treatment which can reduce debris that attaches to rocks and lock up excess nutrients, stopping string algae from taking over. The 473mL bottle can treat 37,800 litres of pond water, total.

For problematic ponds we also have the IonGen electronic water clarifier for Ponds, Pondless® Waterfalls and other decorative water features which drastically reduces maintenance caused by algae without the use of chemicals.